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Spider Photos -
Red Spotted Ant Mimic Spider

Members of the genus Castianeira are considered mimics of large ants, such as carpenter ants, and mutillid wasps, which are known as ďvelvet ants.Ē These spiders walk about slowly the way ants do and then only move fast when disturbed.  Castianeira descripta, the red spotted ant mimic spider only walks with six legs, like an ant. As they walk, their front two legs are raised in the air and quiver quickly up and down like antennae. They also quiver them briefly after they stop walking. They do this to emulate ant antennae and  spiders that imitate ant antennae frequently have conspicuous front legs. It is a characteristic of C. descripta that her front four legs are somewhat transparent and not jet black like the rest of her. Looking at them makes you think more of a wasp than an ant, and perhaps that transparency might also be mimicking wasp wings. Wasps often give their wings a quick shimmy upon landing, just as C. descripta gives her transparent front two legs a quick shimmy when she stops moving. Here's some photos sent in by viewers.  All photos are copyright to their owners and may not be reproduced without permission. Please choose a section.
Unidentified Spiders 2017 Unidentified Spiders 2016 Unidentified Spiders 2015
Unidentified Spiders 2014 Unidentified Spiders 2013 Unidentified Spiders 2012
Unidentified Spiders 2011 Unidentified Spiders 2010 Unidentified Spiders 2009 (1)
Unidentified Spiders 2009 (2) Unidentified Spiders 2008 (1) Unidentified Spiders 2008 (2)
Unidentified Spiders 2007 (1) Unidentified Spiders 2007 (2) Unidentified Spiders 2007 (3)
Unidentified Spiders 2006 (1) Unidentified Spiders 2006 (2) Unidentified Spiders 2006 (3)
Unidentified Spiders 2005 (1) Unidentified Spiders 2005 (2) Unidentified Spiders 2005 (3)
Unidentified Spiders 2004 (1) Unidentified Spiders 2004 (2) Unidentified Spiders 2003
Unidentified Spiders 2002 Unidentified Spiders 2001  
Spiders in Amber Closeups Ant & Wasp Mimicking Spiders
Argiopes/St. Andrew's Cross Barn Funnel Weaving Spider Basilica  Spiders
Bird Dropping Spiders Black & Brown House Spiders Bolas Spiders
Brown Recluse Spiders Candy Stripe Spiders Common House Spider
Crab Spiders Cyclosa Conica Daddy Long Legs
Daring Jumping Spiders Dew Drop Spiders Fishing Spiders
Funnel Web (Aus) Furrow Spider Garden Orb Weavers
Ghost Spider Giant House Spider Golden Orb Weavers
Grass spiders/Funnel Weavers Ground Spiders Hacklemesh Weavers
Hobo Spiders Huntsman Spiders Jewelled Spiders
Jumping Spiders Lace Web  Spiders Ladybird Spiders
Leaf Curling Spiders Long Jawed Orb Weavers Lynx Spiders
Marbled Orb Weavers Micarathena Mouse Spiders
Mygalomorphs Net casting Spider Neoscona Semarak
Nursery Web Spiders Parson Spiders Pirate Spiders
Pseudoscorpion Purseweb Spider Red & Black Spiders
Redback Spiders Red Spotted Ant Mimic Spiders Running Crab Spiders
Scorpion Spiders Segestria Florentina Solfugids/Camel Spiders
Southern House Spiders Spider Tats Spitting Spiders
Steatoda Tailless Whip Scorpions Tarantulas
Tengellid Spiders Titiotus (Recluse look alike) Two Spined Spiders
Trapdoor Spiders Tree Trunk Spider Venusta Orchard Spiders
Wandering Spiders White Tailed Spider Widow Spiders
Wolf Spiders Woodlouse Hunters Yellow & Broad faced Sac Spiders
Zoropsis spinimana

Zygiella x-notata



12 June, 2017:
Hi this is the second spider I've found like this crawling out from in my baseboards in the living room around my fire place and by the window.  I am concerned it may be poisonous and I've gotten many mixed reviews on what exact species this is cause it looks similar to several spiders I've looked up.  Any help would be greatly appreciated thanks 
Jessica from griffin  Ga.


6 May, 2016:
I took this photo of a spider on my bathroom ceiling, can you identify it? Blacksburg, S.C.

23 May, 2015
Saw this tonight where I work in an elementary school in Madisonville,Ky and was wondering what kind of spider it was? Any info would be greatly appreciated. Thank You, Bill

3 May, 2015
Attached Thanks!

3 May, 2015
Hi! I found this guy in my apartment in Redondo Beach, California and was pretty freaked out! Wondering if you can identify it. Great site thanks so much!

Reply: This is a red spotted ant mimic spider - glen

28 May, 2014:
Can anyone identify im from north east georgia usa


28 May, 2014
Hello, "Go Ahead, Bug Me" suggested your page...and I have a photo of an ant that they identified as a red spotted ant mimic and I wanted to pass on the photo. This was taken on a sheet of "college ruled" paper, so the blue lines are about 9mm apart. I live in SE North Carolina. Thank you for your page. Katie

Reply: No this is not a black widow, it's a red spotted ant mimic spider - glen

18 November, 2013:
Glen, Is this a Black Widow? This spider was found inside the house. It was about a half inch across (the width of the grout on the edge of this tile is 1/4 inch). All of the pictures I've seen show a more bulbous body. We live in Austin, Texas. Regards, Joe

Reply: It's a red spotted ant mimic spider - glen

18 November, 2013:
Hi, I found this pic on the internet and it is identical to what I found in my home in South Carolina, he actually got on me. I'm thinking he was in a web I took down with a paper towel.Any ideas? Thank you

Reply: No this is not a male widow, it's a red spotted ant mimic spider - glen

2 September, 2012:
Hi, does this look like a male Widow to you. You answer will determine where I release him, out back or down in the boonies!



7 May, 2012:
Can you tell me what kind of spider this is? Found it near our kitchen window and the total length including legs is about 1 in. We live in SC... In case the region helps.



7 May, 2012:
Would you buy chance know what spider this is?



15 April, 2012:

Here is a spider I found in my house. I don't think it's all that dangerous, but just want to make sure because I have two young daughters playing around on the floor. Thanks.


21 May, 2010:
I initially thought it was a typical Houston, TX jumping spider until after I smacked it with a notepad. I noticed it was very black with that red stripe on its back. It seemed to be hairy/bulky, not the exoskeletal, shiny black you see with black widows or redbacks on the web...


3 August, 2009:
Hello, Can you help me identify this spider? I found it in the basement of my home in a suburb of St. Paul Minnesota about 4 days ago. It measures about 1/2 inch from the tip of the front leg to the back leg...about as long as my thumbnail. What I really want to know is if this is some kind of Black Widow and/or a dangerous spider. I know Black Widows are not native to this climate, but it looks so unlike anything I've ever seen in MN before, and I've heard stories about exotic spiders traveling with food shipments. This spider is currently alive and captured under a drinking glass. Can't decide whether to kill it, set it free or take it somewhere for identification. Thank you! Cory

17 May, 2009:
Hello, Could you ID the spider? About 1 to 1.5 inch long. Thanks. Richard


11 October, 2008:
Hello, I found this Spider inside my Home in (central) Texas. I hope i made a good enough picture. On the belly side it has 2 red point ,left and right and underneath in the middle of those a little white dot. it has this red streak on its back. it has those partial brown front legs. Not sure if that will help,it run very fast and got very aggressive in the glass(who would`t). The only black and red spider I know is the black widow,and that's just what the pest control and animal control said when they saw it,we all not sure what it is. i hope you can bring some closure in identifying this spider. Questions i have are is it a black widow,what is it ,is it venomous? couple weeks back i saw two tiny baby spider ,there were all black,not sure if there is a conection. Thank you so much in advance Ivonne

Reply: This is Castianeira descripta,  the red spotted ant-mimic spider.


Reply: As per the posts lower on this page, that is a Castianeira descripta ant-mimic
20 July, 2008:
Hi Glen, I love your spider website! I am a lifelong spider enthusiast and am usually good at tracking down what family a spider is in, however I was utterly flummoxed today when I saw this spider in the shower. It's body was about 1/4 inch. I live in central Arizona near Phoenix. Any ideas? Thanks so much, Terry


Reply: This is Castianeira descripta ant-mimic spider.

14 June, 2008:
Hope you can help me! Thanks so much!


Reply: As per the posts lower on this page, that is a Castianeira descripta ant-mimic
spider. Nathan

13 July, 2006:
It was in the house at night. My son saw it crawling along the floor. We live in Schertz, TX (near San Antonio). Thanks. attachment contains pics< G. Jackson


Reply: This is another red spotted ant mimicking spider, Castianeira descripta

5 May, 2006:
I found this nasty thing on my wall. I saw on your website something similar but the on your website but is slightly different. Iíve done a major web search but Iím just not sure. We just moved here and Iím worried about my 5 yr. old and little puppy. Iím hoping you can enlighten me in identifying this. Thanks, Pamela

Reply: The red-striped spider sent in on May 5th is an red spotted ant mimicking spider, Castianeira descripta


5 May, 2006:
I found 2 of these spiders in my home this week and I'm concerned they are Australian redbacks. Please help identify if you can.

Reply: Looks very similar to the Castianeira occidens  - Clubionidae (Sac Spiders)  on this page.

4 August, 2005:
Hi Glen, I found this in my house (in Austin Texas), and while doing research on the internet I came across your site. Can you please tell me what kind of spider it is? It was small, about the size of a dime. Thanks, Marc

Reply: Looks very similar to the Castianeira occidens  - Clubionidae (Sac Spiders)  on this page.

29 July, 2005:
Ok. I know those photos were pretty bad... I took a few more, and these look like they may aid in identifying it.